Currently, organic electroluminescent displays (OLED) have enjoyed the most popularity in the display field owing to their excellent properties such as low power consumption, high color saturation, wide viewing angle, small thickness, and the ability to achieve flexibility. Current OLED devices have a service life of over 100,000 h and a storage life of over 50,000 h, which are yet relatively shorter than that of liquid crystal displays and plasma displays. This, as a consequence, still serves as one of the significant factors restricting commercialization of OLED.
Ingredients such as water vapor and oxygen in air greatly affect the life of OLED due to the following reasons: firstly, during operation of an OLED device, electrons are injected from cathode, which requires the work function of the cathode to be as low as possible; however, the metal materials for making cathode such as aluminum, magnesium, calcium and the like, generally have active chemical properties, and therefore are susceptible to erosion in air or in other oxygen-containing environments, especially to electrochemical erosion in an environment containing water vapor; secondly, oxygen and water vapor may further chemically react with organic functional layers in OLED such as light-emitting layers, hole transport layers and electron transport layers, which will deactivate the OLED device.